In the effort to save the planet from carbon emissions, chefs are saying eat less feedlot beef. That’s because feedlot beef is by far the biggest creator of carbon gases. Fed on corn instead of the grass it was meant to eat, cows simply belch and pass wind a lot, creating much of the CO2 that’s harming the earth. Bon Appétit Management Co. and other corporate food-service operators are turning to lower-carbon foods like chicken in an effort to change eating habits while reducing their carbon footprints.